The present invention generally relates to a sorter and more particularly, to a sorting apparatus of a shiftable bin type having a plurality of bins or trays (referred to as bins hereinafter) movably supported for vertical movements with respect to an end portion of a transport section adapted to receive copy paper sheets dishcarged from a copying apparatus for transport thereof in one direction.
As one example of the sorting apparatus of a shiftable bin type as referred to above, there has conventionally been proposed a sorter in U.S. Pat. No. 4,343,463 in which, for a compact construction, etc., respective bins or trays are arranged to move in such a manner that the bin confronting a copy paper sheet feed-in portion is widely spaced from the bin located immediately thereabove, while being disposed relatively close with respect to other bins when the bin is positioned at either side of the copy paper sheet feed-in position.
In the known sorter as described above, the respective bins are arranged to be close together to a compact size, while due to absence of particular consideration with respect to removal of copy paper sheets, there is a problem that a troublesome procedure is required for a problem that a troublesome procedure is required for withdrawal of the sorted copy paper sheets from the respective bins, resulting in such an inconvenience that some small sized copy paper sheets not readily noticed may be left unremoved in the bins in certain cases.
Meanwhile, in order to prevent any copy paper sheets left unremoved in the respective bins, there has also been conventionally proposed provision of a sensor means for detecting presence of copy paper sheets. For example, in Japanese Patent Laid-Open Publication Tokkaisho No. 56-46256, reflecting type sensors are provided for each of bins, while in Japanese Patent Laid-Open Publication Tokkaisho No. 56-144448, a light transmitting type sensor is provided on the sorter main body, with openings being formed in the respective bins at positions corresponding to the sensor optical axis.
The prior art arrangements as referred to above, however, still have such problems that in the former, cost increase is undesirably involved with a sufficient room not being available for space, while in the latter, a high performance sensor is required owing to the prolonged optical axis, and even when presence of the copy paper sheet is detected by the sensor, it is still required for an operator to visually check each time in which bin the copy paper sheet is left unremoved. Furthermore, there is such a possibility that the sensor may be damaged due to troubles in the functioning of the bins.